The present invention relates to the preparation of an aqueous emulsion of acrylate polymers, methacrylate polymers or butadiene polymers by employing hydrolyzed vinyl acetate-alkali metal olefinsulfonate copolymer as an emulsifier.
In an emulsion polymerization it has been known to polymerize monomers in the presence of emulsifier and initiator in an aqueous medium, and also been known that the emulsifier used in the polymerization remarkably has a great influence on the properties of emulsion. Polyvinyl alcohol (hereinafter referred to as PVA) is one of the most popular emulsifier for emulsion polymerization of vinyl acetate and vinyl chloride, but it is not effective for acrylic esters, methacrylic esters or butadiene. As an emulsifier in emulsion polymerization of acrylic esters, methacrylic esters or butadienes, noionic or anionic surface active agents have been usually employed.
An emulsion obtained by such a method is useful for an adhesive, a coating material or a textile treating agent, but has poor characteristics in storage stability, viscosity stability, freeze-thaw stability and dilution stability. Therefore, the greatest care has to be paid in handling such emulsions.